Moles and Mass

• What does the term "mole" refer to in chemistry?


  A unit used to measure the amount of chemical substance
• How is the mole similar to other units of measurement like meters and seconds?

  It measures the amount of substance, just as meters measure distance and seconds measure time
• How many particles are contained in one mole of a substance?

  1. 02 times 10 to the 23 particles
• What types of particles can be referred to as "particles" in the context of moles?

  Atoms, molecules, ions, or electrons
• If you have one mole of carbon, how many atoms of carbon do you have?

  1. 02 times 10 to the 23 atoms of carbon
• What is Avogadro's constant?

  It is the number of particles in one mole, which is 6.02 times 10 to the 23
• Why is Avogadro's constant significant in chemistry?

  Because the mass of that many particles of any substance equals its relative atomic or formula mass in grams
• What is the weight of one mole of carbon dioxide (CO2) with a relative formula mass of 44?

  44 grams
• How can you calculate the number of moles in a sample?

  By dividing the mass of the element or compound by its relative formula mass (mr)
• If you have 42.5 grams of ammonia (NH3), how many moles do you have?

  1. 5 moles
• How do you find the mass of 3 moles of carbon dioxide (CO2)?

  Multiply 3 moles by the relative formula mass of CO2, which is 44 grams
• What is the mass of carbon in 3 moles of carbon dioxide (CO2)?

  36 grams
• How can you find the mass of oxygen in 3 moles of carbon dioxide (CO2)?

  By subtracting the mass of carbon from the total mass of CO2
• What does a chemical equation represent in terms of moles?

  It represents the ratios of moles of reactants and products
• In the reaction of magnesium with hydrochloric acid, how many moles of hydrochloric acid are needed for 2 moles of magnesium?

  4 moles of hydrochloric acid
• How many moles of magnesium chloride are produced from 2 moles of magnesium reacting with hydrochloric acid?

  2 moles of magnesium chloride
• How many moles of hydrogen gas are produced from 2 moles of magnesium reacting with hydrochloric acid?

  2 moles of hydrogen gas